I agree totally with [member=75283]4nthony[/member] 's observations. The algorithm is very sensitive, which I think reflects the shorter-attention-spanned users.
You have a few main interests (and channels that work with them) and mostly watch those things. Then all it takes is watching one thing about some other topic to get flooded with suggestions for that, leaving the others behind.
I'm all over the place. Woodworking, metal working (machining and welding), 3D printing, cop watchers and 1st amendment auditors, bullet throwers :

, automotive, cycling, stand-up comedy, etc. Then I watched a video about restoring a lawnmower...and bang, tons of them.
As far as dwindling content, yes I see it, but it's not just woodworkers. Some of my favorite channels have slowed to a crawl. This Old Tony, for example. He has great content and been on a long time, then dropped to once a month or so?
I think it has become about money. The ones who make it big, from very humble beginnings, seem to get a lot of support from Patreon, channel memberships, their own website, etc and they just don't bother anymore, since they don't need to. Others get disenfranchised with it because they aren't making the money they thought was possible.
Others have branched off into other interests, which may or may not hold the attention of some of the followers.
Matt Cremona, for example, started as a mostly hand tool furniture builder in his home/garage shop. As a tangential thing, he got into urban logging and milling the lumber. This lead to building a huge bandsaw mill and then a new log harvesting trailer. The growth overwhelmed his space, so he rented a warehouse, which included selling wood slabs and furniture parts. A move to a new house, with the remodel of that came next, and now he's on to building a huge barn on the property. I obviously have been there through it all, but if your only interest was hand planes and Chippendale furniture, you were out long ago.
I don't mind the adds which are related to the content, but the beard trimmers, food boxes, and VPN services need to go.